This invention relates to a circular knitting machine for forming knitted fabrics having patterning effects, with a device for increasing the size of the pattern obtainable on the fabric.
In circular knitting machines, the patterns are obtained on the manufactured product by suitably selecting the needles. In particular this is done on large diameter machines which comprise a number of thread feeds, for example of different colours, and where the knitted fabric obtained is of relatively large size.
A problem which arises in these machines, whether of the type in which the fabric is obtained in tubular form and then cut along a generatrix, or of the type for forming open tubular fabric, is that of obtaining a sufficiently large pattern. in this respect, the width of the pattern is limited by the possibility of needle selection, i.e. in substance by the number of available butts on the needle or jacks for selecting the needles, this number being limited for constructional reasons, and by the number of selection levers which can be disposed in the narrow space available without obstructing each other. The pattern height is a function of the number of feeds, in the sense that if the feeds are increased due to the fact that more courses are knitted simultaneously the pattern height is also increased, except where the pattern is obtained with a colour effect, and then the respective heights are reduced to one half in the case of two colours, one third in the case of three colours and so on.